Business Segments, Gross Operating Margin (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Gross Operating Margin [Abstract]
Revenues									$ 47,951.2		$ 47,727.0		$ 42,583.1
Subtract operating costs and expenses									(44,220.5)		(44,238.7)		(39,367.9)
Add equity in income of unconsolidated affiliates									259.5		167.3		64.3
Add depreciation, amortization and accretion expense amounts not reflected in gross operating margin									1,282.7		1,148.9		1,061.7
Add impairment charges not reflected in gross operating margin									34.0		92.6		63.4
Subtract net gains attributable to asset sales and insurance recoveries not reflected in gross operating margin									(102.1)		(83.4)		(17.6)
Add non-refundable deferred revenues attributable to shipper make-up rights on major new pipeline projects reflected in gross operating margin									84.6	[1]	4.4	[1]	0
Subtract subsequent recognition of deferred revenues attributable to make-up rights									(2.9)		0		0
Total segment gross operating margin									5,286.5		4,818.1		4,387.0
Reconciliation of total Segment Gross Operating Margin [Abstract]
Total segment gross operating margin									5,286.5		4,818.1		4,387.0
Adjustments to reconcile total segment gross operating margin to operating income:
Subtract depreciation, amortization and accretion expense amounts not reflected in gross operating margin									(1,282.7)		(1,148.9)		(1,061.7)
Subtract impairment charges not reflected in gross operating margin									(34.0)		(92.6)		(63.4)
Add net gains attributable to asset sales and insurance recoveries not reflected in gross operating margin (see Note 20)									102.1		83.4		17.6
Subtract non-refundable deferred revenues attributable to shipper make-up rights on major new pipeline projects reflected in gross operating margin									(84.6)	[1]	(4.4)	[1]	0
Add subsequent recognition of deferred revenues attributable to make-up rights									2.9		0		0
Subtract general and administrative costs not reflected in gross operating margin									(214.5)		(188.3)		(170.3)
Operating income	921.0	937.7	884.3	1,032.7	915.5	819.9	774.2	957.7	3,775.7		3,467.3		3,109.2
Other expense, net									(919.1)		(802.7)		(698.4)
Income before income taxes									$ 2,856.6		$ 2,664.6		$ 2,410.8

[1] Several of our major new liquids pipeline projects experienced periods in 2013 and 2014 where shippers were unable to meet their contractual minimum volume commitments.